Device might offer some troops an alternative to amputation

Spc. Michael Krapels, a member of the Chosen Company, 2nd Battalion, 503rd Infantry Regiment, works to strengthen his leg while wearing an Intrepid Dynamic Exoskeletal Orthosis during physical therapy at the Center for the Intrepid at Fort Sam Houston, Texas in August.

Related

BAUMHOLDER, Germany — Johnny Owens thought about quitting his work as a physical therapist after several of his patients, each of whom endured up to a year of painful rehabilitation, chose to have their legs amputated after all.

Equally frustrated was Owens’ colleague, Dr. (Lt. Col.) Joseph R. Hsu, the head of orthopedic surgery at Brooke Army Medical Center in San Antonio. Hsu had performed dozens of operations to reconstruct servicemembers’ badly injured limbs, only to have them later demand amputations. In the rehabilitation ward, Hsu said, these patients would see amputees performing better and experiencing less pain with the help of high-tech prosthetics.

“For me,” he said, “it shook the foundation of being a physician. You start to question whether the reconstruction harmed this person.”

Hsu and Owens turned to Ryan Blanck, a prosthetist at the hospital, to see whether there was a device that could help troops whose limbs were rebuilt.

There wasn’t, Blanck said.

More than 1,300 troops have had an amputation since the start of the Iraq and Afghanistan wars. Their desire to return to athletic lives and to continue to serve in the military in some cases, combined with a generous budget from the Department of Defense, has pushed prostheses to new levels of inventiveness and performance.

Still, more servicemembers have had limbs reconstructed than amputated, military doctors say. Dr. (Col.) James Ficke, chief of a task force that found an increasing number of troops in Afghanistan are suffering severe wounds that result in limb loss, said that for every amputee, there are at least four or five servicemembers who undergo limb salvation surgery.

Little research available

Advertisement

But there has been little research into devices that might boost the functionality of rebuilt limbs. An unintended consequence is more servicemembers having amputations months or even years after their initial injuries. According to a study in the December 2010 issue of Military Medicine, 15 percent of combat-related amputations are “delayed” or “late” amputations — defined as when limbs are removed three or more months after an injury. The majority of them are to the legs, below the knees.

Blanck and his colleagues hope to reverse this trend with a device that uses many of the same design principles as advanced running prostheses, including carbon fiber struts and a foot plate, which provide stability and power to the injured leg. Like something out of a comic book, it’s dubbed an exoskeleton, and worn over the limb, a hybrid of brace and prosthetic.

“You can feel the power it generates,” said Blanck, who has worn it himself. “When you step, it feels as a though your foot wants to jump up.”

Since January 2010, about 150 servicemembers have been outfitted with the device, called the Intrepid Dynamic Exoskeletal Orthosis, or IDEO.

Built by Blanck, the IDEO allows soldiers and Marines who could hardly walk on their rebuilt legs to run, jump and perform high-intensity exercises. More than 20 of them have returned to their units and deployed to combat zones, including members of elite units, such as the Navy SEALs and Army Rangers.

The biggest challenge now, Owens says, is getting to the injured troops before they choose amputation.

“Battlefield amputee”

On Sept. 11, 2010, a Special Forces staff sergeant led a foot patrol into a village in the southern part of Helmand province, Afghanistan. The soldiers came upon several compounds that were unusually calm. The absence of people was evidence that the place was rigged with improvised explosive devices, said Ryan, who asked not to be identified because of his work.

His only interpreter was about to enter one of the compound’s gates. Ryan ran to stop him, and his foot triggered the pressure plate of a bomb.

“I hit an IED that was meant for him,” he said. “It was in the ground right by the gate — you would have to step on it or over it to get through. And our metal detectors missed it.”

The blast tore through his right leg, leaving a mangled mass of splintered bones, shredded muscles and charred skin. He can still remember the smell of carbon and ammonia from the fertilizer bomb, he said, and the choking dust.

“I was labeled a battlefield amputee,” he said.

Ryan was taken to a local hospital, then to another in Germany, and then to Brooke Army Medical Center, completing what has become a familiar itinerary for American soldiers badly wounded overseas.

At BAMC, he fought with doctors to keep his right leg. They agreed that it could possibly be rebuilt.

Over the next 10 months, Ryan said, he underwent more than 20 operations to repair bones in his leg, ankle and foot.

But even after the bones had healed, Ryan found himself unable to do much with his injured leg.

“I’d try and walk and I’d step with my left leg and just drag my right leg behind me,” he said.

Shooting pain rippled through his body with each step, and his leg ached even while he slept.

“There was so much pain involved, and I just got to the point where I couldn’t bear it,” he said. “I battled with the idea of an amputation for a long time.”

Running within minutes

Orthopedic surgeons have become much more skilled at reconstructing bones in the lower leg, Hsu said. But the trouble is that the explosions do not only break bones, but they also rip apart important muscles and tendons, as well as nerves and cartilage, in the leg and foot.

“Even though the limb is straight and healed and out to length,” Hsu said, “the person still has limited function.”

Blanck’s device, the IDEO, compensates for the lack of leg muscle by emulating the natural action of the calf. Weighing about a pound, the device consists of a cuff that wraps around the leg, just below the knee and a tongue-like foot plate that goes inside the shoe or boot. The key to it is a set of carbon fiber rods, or struts, that connect to the cuff and the foot plate. As the heel steps down, the rods collect energy and then release it, propelling the foot forward, similar to a spring.

Designed to support much of the wearer’s weight, the device also helps alleviate pain, which can cascade when damaged or taxed nerves fire automatically, bombarding the brain and central nervous system.

“Because we are able to break the mechanical pain,” Hsu theorized, “they start to heal their neurogenic pain on their own.“

Ryan said that he could feel the IDEO’s effect from the moment he strapped it on.

“When I took my first step,” he said, “it was very awkward, because I had all this power in my leg that I hadn’t had before.”

Within minutes, he said, he was jogging. A majority of the patients who have worn the device have had similar success, Blanck said, but how far they progress depends on the extent of their injuries and subsequent physical therapy.

A study performed at BAMC’s Center for the Intrepid found that the IDEO improved performance 10 percent to 37 percent when compared with three commercial braces. Performance measurements included walking speed over smooth and rocky terrain, the ability to climb stairs, the 40-yard dash and other tests of speed and agility. Blanck said the study has been submitted to the Journal of Bone and Joint Surgery, but a publication date has not been set, and a patent for the IDEO has been submitted through Fort Detrick, Md., with the Army owning the majority of the rights.

Game changer

Dr. Michael Bosse, clinical chair of the Major Trauma Extremity Research Consortium and an orthopedic surgeon at the Carolinas Medical Center in N.C., said that the IDEO has the potential to be one of the most significant medical advancements from the wars in Iraq and Afghanistan.

“This will change the game for patients that don’t get amputations,” said Bosse, who has seen the device in action and has no financial stake in it. “And the long term benefits for society are potentially huge.”

Bosse said further research is needed to see whether the results at BAMC can be replicated in civilian hospitals. But he sees no reason why it shouldn’t work for civilians whose legs have been crushed in car and motorcycle wrecks or industrial accidents. Before the invention of the IDEO, the most doctors could offer these patients was a plastic brace, which secured the ankle but did not provide any energy assistance with walking or running, Bosse said.

He said amputation is a last resort for civilians and troops, estimating that 80 percent of trauma patients have had some sort of limb reconstruction.

“We really need to commit research funds for this thing,” Bosse said. “We’ve done all this research to improve those that are undergoing amputation, but have done nothing for the salvage patients. And this is the group that needs the most attention.”

Game on

Blanck continues to tweak and improve the device’s design as he receives feedback from wearers. Each IDEO, which must be custom-fit, costs about $5,000 and lasts three to five years when used under normal conditions — meaning not downrange. For servicemembers who are deployed, he keeps extra models and spare parts around that he can quickly send to them.

Blanck said most patients are nervous about taking their first step, because they know what looms for them if the device fails: a potential amputation.

But the first steps are only the beginning. They must also learn a new gait that allows them to pivot with their hips, compensating for the fact that their ankle is secured within the brace.

“We retrain them like kids learning to run for the first time,” Owens said.

As they become more confident with the device, Owens puts them through more difficult and rigorous drills, such as ones that focus on cutting and exploding off the injured limb.

Ryan said that he had recently run a 10-minute mile and begun to jump with the device. He plans to return to his unit.

“I’m going to head back to Afghanistan and continue what I was doing before,” he said. “I’ll just be a little more careful about where I step.”

Just two months ago, he recalled, he was considering an amputation. Owens talked him out of it.

“I knew we could get him to this point,” Owens said. “If Dr. Hsu gets the bones to heal and the wounds to close, we can strap the brace on, and then it’s game on.”